I'm thinking about a movie with Kevin Costner: "The Guardian". This kid has failed his Coast Guard rescue swimmer cert 2 times previously, and is now trying for the last time. In the scene I'm thinking about the instructor "goes berserk" while the kid is trying to rescue him; he's taking him under, drowning is a distinct possibility, and it's getting pretty intense. The kid gets P.O.'d and punches the instructor in the face. It stuns the instructor and the kid is able to "rescue" him. Of course he's now worried his instructor is going to be P.O.'d and fail him anyway. However, the instructor gets out of the pool with a bloody nose and walks over to the kid, an angry look on his face, but then the instructor smiles and says "good job". It was a great scene.